Refrigeration apparatus



Dec. 24, 1957 E, s, DYBWG REFRIGERATION VAPPARATUS Filed Feb. 8, 1956 u 1. irri) United States Patent REFRIGERATION APPARATUS Edwin S. Dybvig, Dayton, Ohio, 'assignor to General Motors Corporation, Detroit, Mich., a corporation of Delaware Application February s, 1956, serial No, 564,155

7 claims. (c1. zii-4) ice walls of a refrigerator cabinet. Figure 2 is an enlarged partial cross sectional view of a bag wall.

Referring now to the drawings, Figure l shows a preferred form of a bag insulation structure made in accordance with the present invention. It consists of a two-compartment bag having outer walls 10 and 12 and an intermediate wall 14, preferably heat sealed together at the edges thereof as indicated at 16. The compartment 18 formed by the outer wall 10 and the inner wall or membrane '14 is preferably iilled with a porous solid insulation medium such as relatively loose rock wool or fiberglas and is further charged with a gas having a low heat conductivity coeicient such as dichlorodiiuoromethane or sulfur hexafluoride, which is hermetically sealed therein. The wall 10 and inner membrane 14 are preferably formed of a flexible material which is impervious to the passage of the insulating gas, air and moisture therethrough.

v The walls 10 and 14 may be advantageously made of a laminated structure as shown in Figure 2 wherein a thin filler or layer of Mylar 20 (a polyester of ethylene glycol bag as yan insulation medium which is placed between a pair of `spaced walls, as for example, the inner and outer walls of a refrigerator cabinet, is that of allowing for the expansion ofthe gas therebetween due to changes in the external conditions of'temperatures and pressure so as to prevent a rupture of the bag or a distortion or bulging of the walls. A further problem is to insure that substantially all of the space between the walls is occupied byan insulating material having a heat conductivity coeicient less than that of air, at all external conditions of and terephthalic acid) which is suitably impervious to the passage of the insulating gas, is coated on both sides with vapor deposited aluminum or other suitable metal 22 which in turn is coated with a thin layer 24 of a material impervious to the passage of air or moisture, such as polyethylene, Saran (a copolymer of vinyl chloride and vinylidene chloride) or Hycar vinyl (a mixture of vinyl chloride-vinyl acetate copolymer and butadiene-acrylonitrile copolymer). The laminated walls of this construction are suitably impervious to the passage of the -insutemperature and pressure to which the'apparatus may be exposed in use whereby a maximum insulating effect is obtained for a given amount of insulating space.

In general, one approach to overcoming thel above problems is to interpose a quilt or layer of compressible insulation material between the bag and one of the walls so that as the gas filled bag expands, the quilt, due to its compressible nature, will take up the increased volume of the bag and thereby prevent subjecting the walls and the bag to undue pressure. It is highly desirable to associate thebag and the quilt so as to form aunitary insulation member and thereby avoid handling two or more separateinsulation members in the assembly of the refrigerator apparatus.

It is an object of the present invention to overcome theabove problems by providing a unitary bag having at least two side by side compartments, separated from each other by alcommon imperforate wall or membrane, charging one of the compartments with an insulating filler material and a gas of low heat conductivity and hermetically sealing the same, and incasing in the other compartment a cushion or layer of compressible insulation material. The outer wall of the gas filled compartment and the inner wall or membrane thereof are formed of a material or materials impervious to the passage of the insulating gas, air and moisture therethrough, and the outer wall of the other compartment is preferably substantially impervious to the passage of moisture therethrough but issvuffcientlype'rvious to 'the passage of air topermit the compartment"to'breathe to equalize the pressure between the latter compartment and the atmosphere.

Further objects and advantages of the present invention will be apparent from the following description, reference being had to the accompanying drawings, wherein a preferred form of the present invention is clearly shown. Figure 1 is a perspective view with parts broken away showing a form of bag type insulation associated with the lating gas, air and moisture and may be readily heat sealed.

In the other compartment 19 is incased a suitable compressible, solid porous material such as a quilt or layer of rock Wool or berglas, sponge rubber and the like. The outer wall 12 is preferably formed of a moisture impervious material such as polyethylene having one or more pinholes or breather openings as indicated at 13 which are of suicient size to permit the passage of air and substantially prevent the passage of moisture therethrough. The materials used as the outer coatings of walls 10 and 14 and the wall 12 should, of course, be chemically compatible so that they may be readily heat sealed together. It is to be understood that the insulation bag shown in Figure l is, in use, placed between rigidly spaced inner and outer walls 26 and 28 of a refrigeration cabinet or the like. It may readily be seen that when the bag wall 12 i's disposed adjacent one wall 26 of the cabinet while the bag wall 10 is disposed adjacent the other cabinet wall 28, no appreciable air space is confined by the cabinet walls. Further should the gas in compartment 18 expand due to an increase in the surrounding temperature or a reduction of the atmospheric pressure, the increase in volume thereof is taken up by the compressible nature of the adjacent compartment 19 whereby undue stresses on the bag and the walls of the cabinet are effectively prevented. A bag made of lthe material described is relatively tough and able to resist being punctured during normal handling and assembly operations. However should yadditional protection be desired, the bag may be further incased in a suitable paper bag without materially Iincreasing the cost thereof.

anima@Y 3 In manufacturing the bag it 'is preferable that the compartment containing the insulating gas be lilled and sealed before the insulation is placed in the compartment 19 so that the compartment .18 can .be checked yfor leaks more conveniently. I

It may also be seen that in some instances, particularly when a relatively thick 'insulation bag Yis required which isto besubjected to relatively extreme changes in temperature and pressure, a bag `may 'be advantageously vused having a plurality of compartments wherein 'a compressible layer is disposed in compartments on each side of the bag or as an intermediate compressible layer.

The bag insulation units of the present inventionrmay be made of any suitable size so as toperm'it'a convenient assembly of la given insulation structure `and as shown in NFigure '1, a plurality of bags are kpreferably arranged in -edge to edge relationship.

Whilethe form of embodiment oftheinvention as .herein disclosed 4constitutes a preferred form, it is 'tolbe .understood that other Vforms may be adopted, as may come Within the scope of'the claims-whichfollow.

What is claimed is as follows:

1. Ina refrigerator, an vouter wall, an 'inner wall, an insulation-between-said walls, said-'insulation comprising a unitary bag having at least ltwo s'ide `by side icomp'artments separated from each other b y a common 'membrane, -a -irst of said vcompartments `containing a vi'iller having voids anda gas havingathermal conductivity less 'than that of air Lfilling said voids, said first mentioned compartment being formed of -substance `impervious to the passage 'of said gas, air and moisture therethrough, the VVother of said 4compartments incasing a compressible insulation material whereby said 'rst `mentioned Acompartment may vexpand against `-said Iother compartment, said other compartment having an outerlwall thereof made of'a material substantially impervious to the passage lof moisture therethrough and having breather openings therein for equalizing the pressure between -said "other compartment andithe atmosphere.

2. In a refrigerator, Van outer wall, yan-inner'walL'insulation between sai-d walls, said insulation comprising the unitary bag having a iirst wall comprising polyethylene, and second and intermediate walls each formedo'" a plurality of layers `including 'av-layer-comprising a polyester of ethylene glycol and terephthalic -acid and a layer of material taken from -theclassconsisting of polyethylene, vinyl chloride-vinylidene chloridecopolymer and fa mixture of vinyl chloride-.vinyl acetate copolymer and butadiene-acrylonitrile copolymer, isaid vsecondand intermediate walls forming a hermetically -sealedrst compartment, a -ller in'said first compartment yhaving voids, saidvoids being filled with gaseous dichlorodiiiuoromethanm said first and lintermediate walls forming a second 'compartment, said `second compartment incasing acompressible insulation material -whereby said `first mentioned compartment may expand against said'other compartment, Ysaid first bag wallhaving a breather opening ytherein for/equalizing the pressure between said secondcompartment and the atmosphere.

3. In a refrigerator, anouter wall, an inner wall, yinsulation between fsaid wa1ls,said insulation'comprising a unitary bag having a iirst wallcomprising polyethylene, .second and Yintermediate walls :each formed of a Aplurality lof layers including a layer comprising pol-yethylene and a layer comprising a polyestero'f-ethylene glycol and terephthalic acid, said -second and intermediate walls forming a rst hermetically sealed compartment, la-filler iin lsaid `first compartment'having voids, said -voids being lled with gaseous dichlorodifluoromethane, said first and intermediate walls forming a second compartment, said second compartment incasing a compressible insulation material whereby said first mentioned compartment may expand within said other compartment, said irst bag wall having a breather opening therein for equalizing the pressure between said second Vcompartment and the atmosphere.

4. In a refrigerator, an outer wall, an inner wall, spaced from said outer wall, insulation 'between said walls, said insulation comprising a unitary bag having at least two side by side compartments separated from each other by a common membrane a first of said compartments being hermetically sealed and containing a loose inert fibrous filler material and a gas having a thermal conductivity less than that of air, said tirst compartment being formed of substance impervious of the passage of air, moisture and saidgas therethrough, the other of said compartments enclosing a compressible vaporous material whereby said tirst compartment may expand toward said other compartment, said other compartment having an vouter wall formed of a substance capable of substantially preventing the passage of moisture therethrough and having breather means for equalizing the pressure between said other compartment and the atmosphere.

5. Bag insulation adapted to be interposed between inner and outer walls of a refrigerator comprising a unitary bag having atleast two side by side compartments .separated from each other by a common membrane, a first of said compartments containing a filler having voids and a gas having a thermal conductivity less than that of air filling .said lvoids, :said rst mentioned compartment being formed of substance impervious to the passage of the said gas, air and moisture therethrough, the other of said compartments incasing a compressible ,insulation material whereby said first mentioned compartment may expand against the said othercompartrnent, said other compartment having an outer wall thereof made of a material substantially impervious to the passage of moisture therethrough and having breather openings therein for equalizing the pressure kbetween said other compartment and the atmosphere.

f6. Bag insulation adapted to be interposed between inner and'outer ywalls of a refrigerator, comprising a unitary bag having a v,hermetically sealed compartment and a .vented `compartment separated by common Vilexible means, said ,sealed compartment containing a iiller ,having voids thereinand a gasin said voids ,havingfa thermal conductivityless than that of air, said vented compartment enclosing a compressible insulation against which said-sealedcompartment may expand.

7. An insulation structure comprising a pair of wall members arrangedin spaced relation, an insulation member betweenysaid members, comprising an integral flexible bag having a hermeticallysealed portion and a vented portion separated `by common flexible means, said sealed portion containing aiiiller'having voids and a gas in said voids, said vented portion incasing a compressible insulation whereby expansion of .said sealed portion is relieved by said compressible insulation.

References Cited in the lile of this patent UNITED STATES PATENTS 

